Effects of Bacillus subtilis and Chlorella powder on growth performance,immunity,and muscle quality of tilapia

WANG Yan; ZHANG Zhiqiang; ZHU Bingqing; MENG Wei; ZHU Huixia; LIU Jingjing; JIAO Qing; SONG Xutong

doi:10.13557/j.cnki.issn1002-2813.2025.23.013

Abstract：The experiment aimed to investigate the effects of the combined addition of Bacillus subtilis and Chlorella powder on the growth performance,non-specific immunity,and muscle quality of tilapia.A total of 360 healthy tilapia with similar body weight were randomly divided into four groups,with three replicates per group and 30 fish per replicate.The control group was fed with basal diet,while experimental groups A,B,and C were fed with basic diet supplemented with 0.15%Bacillus subtilis,1.5%Chlorella powder,and 0.15%Bacillus subtilis+1.5%Chlorella powder,respectively.The pre-test period was 14 days,and the formal trial period was 90 days.The results showed that compared with the control group,the final weight of tilapia in the experimental groups B and C was significantly increased(P<0.05),and the specific growth rate in the experimental group C was significantly increased(P<0.05).The weight gain rate in experimental groups A,B,and C was significantly increased(P<0.05),while the feed coefficient was significantly decreased(P<0.05).The activity of lysozyme(LZM)and the content of immunoglobulin M(IgM)in the serum of tilapia in the experimental groups A,B,and C were significantly increased(P<0.05),while the content of malondialdehyde(MDA)was significantly decreased(P<0.05).The activity of superoxide dismutase(SOD)in the experimental groups B and C was significantly increased(P<0.05).The crude protein content in tilapia muscle of the experimental groups B and C was significantly increased(P<0.05).The study shows that adding Bacillus subtilis and Chlorella powder to the tilapia diet can improve growth performance,immunity and muscle quality to varying degrees,and the combined addition of Bacillus subtilis and Chlorella powder has a better effect.